This invention relates to a method of operating a numerically controlled machine tool having tools for processing workpieces, the tools having a plurality of axis and spindle movements which are to be calculated independently of each other to control the tools, the operation of the machine tool being controlled by further operating, auxiliary and control commands. The invention also relates to a machine tool for carrying out the method.
In known methods of operating such machine tools it is usual to use a central machine program, from which the individual tool axes are controlled. Accordingly the corresponding program set is loaded into a core memory, interpreted and carried out. Such a method is, however, relatively complicated and time-consuming, because a new calculation must be carried out at each program step. A conventional program set consists, for example, of a direction that the X-axis and the Y-axis of a tool are to be advanced to a particular extent and the speed along the path of advance is included in the program set. In such a program set, which is loaded into the memory at each step, the way in which the processing is to be executed is also included, that is to say, for example, by drilling, milling or turning.
With each program set, however, the X, Y and, if applicable, also the Z-axis of the tool concerned, and also the other variables, must be recalculated each time. Also, corresponding signals must be returned to the control unit to announce thereto that the corresponding program step has been completed, or alternatively, that errors have occurred, for example tool path deviations, which must be corrected. The execution of such a program step is, therefore, costly and complicated.
Also, the carrying out of such different program steps involves an undesirably large expenditure on hardware and software.